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| 8tonsemi |
 Posted: 05/24/2012 12:45 PM Post subject: SCH. 40 vs ABS |
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Captain
Joined: 16 Feb 2012
Posts: 323
170.72 Spud Bux
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I want your opinion on what you think is better for an advanced spud gun. Run of propane or mapp gas. Sorry this is kind of a nooby question. 
Oh and does Abs really crack instead of explodeing. |
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| budabob07 |
| Posted: 05/24/2012 12:49 PM Post subject: |
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Specialist
Joined: 11 Nov 2010
Posts: 40
90.19 Spud Bux
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| I've heard that ABS cracks instead of exploding and shooting shrapnel everywhere so it would probably be safer. SCH 40 is much more common though. |
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| 8tonsemi |
| Posted: 05/24/2012 12:51 PM Post subject: |
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Captain
Joined: 16 Feb 2012
Posts: 323
170.72 Spud Bux
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| Where I live I can get ABS everywhere |
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| mattyzip77 |
| Posted: 05/24/2012 13:02 PM Post subject: |
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Spudder Extraordinaire
Joined: 28 Jun 2011
Posts: 1255
743.48 Spud Bux
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| If your going to spend the money on a b s, why not just spend a few bucks more on steel??? I have never used a b s on a spud gun, however I heard from multiple forum members that it is alot safer than p v c. |
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| Technician1002 |
| Posted: 05/24/2012 13:15 PM Post subject: |
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Senior Technician
Joined: 04 Apr 2009
Posts: 5037
16777.39 Spud Bux
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| 8tonsemi |
| Posted: 05/24/2012 13:41 PM Post subject: |
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Captain
Joined: 16 Feb 2012
Posts: 323
170.72 Spud Bux
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| I actually have read your thread its great. I meant this to be more of a poll |
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| MrCrowley |
| Posted: 05/24/2012 14:50 PM Post subject: |
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Kaleun
Joined: 23 Jun 2006
Posts: 10056
12577.50 Spud Bux
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Well we already have had loads of topics like this one (that poll people's opinions on the matter). If you can find pressure rated ABS, by all means use that instead of PVC. If you can find DWV ABS (non-cell core), it will be fine on a properly constructed combustion cannons. I would recommend pressure rated ABS or pressure rated PVC for pneumatics but ABS would be the better option.
As for an advanced combustion (propane or MAPP) DWV ABS probably can be used reasonably safely, just make sure to tap any fittings in to double layered areas (where a pipe meets a fitting, for example). |
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| 8tonsemi |
| Posted: 05/24/2012 15:43 PM Post subject: |
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Captain
Joined: 16 Feb 2012
Posts: 323
170.72 Spud Bux
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| Thank you for the help. |
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| boyce123 |
| Posted: 06/03/2012 21:51 PM Post subject: |
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Corporal
Joined: 25 May 2012
Posts: 62
249.31 Spud Bux
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this is the only picture of a failure i've ever seen come up (besides the occasional end cap blowing up), can anyone find what a full chamber failure looks like, with abs or pvc? |
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| Crna Legija |
| Posted: 06/04/2012 0:13 AM Post subject: |
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shots shots shots
Joined: 20 Jul 2008
Posts: 2361
2330.42 Spud Bux
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| PVC will turn to shrapnel, abs just a single crack like above. |
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| MrCrowley |
| Posted: 06/04/2012 0:21 AM Post subject: |
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Kaleun
Joined: 23 Jun 2006
Posts: 10056
12577.50 Spud Bux
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I've had some fittings on a PVC chamber fail at around 100PSI. With three people around it, no one was hurt but I owe that to the fact it was down by our waists and not close to our faces. It does indeed shrapnel.
With your proposed hybrid chamber, you would probably be better off just using the copper piping you planned to use as a sleeve and fibre glassing it. |
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| jackssmirkingrevenge |
| Posted: 06/04/2012 0:36 AM Post subject: |
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aspiring machinist
Joined: 15 Mar 2007
Posts: 21964
41074.75 Spud Bux
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| MrCrowley wrote: | | Well we already have had loads of topics like this one (that poll people's opinions on the matter). |
This is science, opinions shouldn't matter - only cold hard facts  |
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| MrCrowley |
| Posted: 06/04/2012 0:51 AM Post subject: |
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Kaleun
Joined: 23 Jun 2006
Posts: 10056
12577.50 Spud Bux
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Well I say opinions because the facts aren't in question, it is how we choose to interpret them. This of course is aimed at the argument over whether we should use PVC or not due to its failure characteristics and manufacturer warnings about using it with pressurised air (which is essentially about failure characteristics). I think whether one should follow that warning or not is a matter of opinion. 
If anyone has missed out on such an argument, it goes like this:
Person A: If your PVC chamber fails, it will shrapnel with potentially harmful consequences.
Person B: Well it's a good thing then that my chamber is rated for 260PSI and I only use it at 120PSI.
Person A: The same people who put a rating on that pipe also state that it shouldn't be used with pressurised air.
Person B: Well that's because of the failure characteristics, not because air is harmful to the structural properties of the pipe.
Rinse and repeat.  |
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| jackssmirkingrevenge |
| Posted: 06/04/2012 1:11 AM Post subject: |
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aspiring machinist
Joined: 15 Mar 2007
Posts: 21964
41074.75 Spud Bux
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| MrCrowley wrote: | | I think whether one should follow that warning or not is a matter of opinion. |
Fair enough, the question is do we have enough data to make an informed choice? Massive subtle hint wink wink nudge nudge  |
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| boyce123 |
| Posted: 06/04/2012 15:49 PM Post subject: |
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Corporal
Joined: 25 May 2012
Posts: 62
249.31 Spud Bux
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| MrCrowley wrote: | | With your proposed hybrid chamber, you would probably be better off just using the copper piping you planned to use as a sleeve and fibre glassing it. |
i'm not sure if this was directed at me, but i'll reply, i was actually thinking of making an all copper chamber, then i remembered that i don't have any 3" copper fittings, and 3" copper fittings are expensive... this (http://www.spudfiles.com/forums/new-hybrid-design-t24270.html) was meant to be as cheap as possible... but back the the topic on hand. I know what how the pvc is supposed to fail, but i've never seen pictures of a chamber failure. Curiosity led me to wonder the shrapnel size, power, and spread pattern in the case of a full chamber pvc failure. |
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